Magnetic fluid brake



5. 0. SPILLMAN MAGNETIC FLUID BRAKE Aug. 19, 1952 Filed March 22, 1949 UVVENTOR G. C. SPILLMA/V By W A i'fOR/VEY Patented Aug. 19,

" .LMAGKETIC FLUID BRAKE Gordon 0. Stillman; Roselle} N. :1, as signor toiWe'stern EIe'tric GompaIny, Incorporated,:New

Ybik, }N. 72., a-cdrporation or New York mainstream-agar; 22, 1949;:Serial'N6182Z8 '8 Claims.

invention re1at'es to a wire 'tensionih'g ap- Lpa'ratii's 'a'ndmethod land (more 'particularlv'to app'aratilswhrein the wire tension is" controlled tymnauonsm amagnetic field. lnlc'ables'tranding, which is one main'applicatio'n'of the present'invention, a'plurality of'wir'es, fth'e lniimbe'r required "for "a given cable; are passed from their individualfreels throughi'aper- .tures .in a wire grouping face plate and then tlirough stranding apparatus to a takeup unit T supplies the tension for] pulling the "wires "from their lres'pectiv'e "reels. In such machines 'itisiirri'por'tarit to regulate thetension' to a close degree 'to avoid breakingthe wireand 'toiprevent irregularities. in the lay of the 'wiies in the cable.

iln one 'welliknown'tension 'regula'tingfdevice "a jockey arm, which is actiiated'by the variations in wiretension, varies the drag producedon the reel by a friction type brake. As in anybiake .-ofthissgeneral type, theflconstant frictional lenigagement and disengagement of ,the "brake 'ele- :ments cause a wear and tear that requires 'fre- ;quent replacement and presents a serious, problem-ofemaintenance. u I

":It is :an. object of this invention to improve the regulation of tensioning apparatus so'that'itniay beloperated for long .periods' without replacement '-or-lossof-timefor-repairs. v a 1 V *Inoneembodimeritof 'theinven'tiomoil or other --li'quid--having magneticparticles suspended therein is circulated in a closed; circuit by a .'.pump drivenby la:wirereel as the reel ieeds wire'into tarstranding machine. ;At asuitable point'in the wlosed I circuit the liquid passes through a magswnetic field whose-strength is varied by variations =zinv the wire tension, as;forexamp1e by means of :a conventional jockey arm, The magnetic (par- .i-ticl'es,*when'passing through the magnetic field,

now in the National- Bureau of Standards -'I 'e"chnieal-News Bulletin'of May, 1948. Applicant theregoreis not claimingthe basic idea' but does claim the improvemen't represented by the present invnuen.

"Cthr object's andadvanta'ges will bejap'parent from the following detailed "specification when takenfinconjunction with the attached drawing "in which:

(Cl.':2'42-=4'5') Figfl-isasidee1evationaliviewoftlie invention; Fig.2 is' a'plan view of'theinve'iitibn;

Fig.- 3"is-asectional -view ar a, "devicewliich' aids in' maintai'ning the wire at a des ired" tensi'o'n.

5 With "reference to the dra-win'g; "a *r'eel mounted between centering "supports {I 2 and t3. f'Centeringsupport P2 [is positioned o'n-shalft -l "(if pump t5; the pumpbeingsupportedby basepl'ate "22, ar'i'd'utilizes a'spri'ng l' 6"to--*urge-itsinclined 'fsurfa ce into *a 'fricti'ona'l "fitwith 'the" reel H. Rigidly mounted on the pumpsh'aft I 4" is" "porting" p at-e 2'! having two *couri't'erbala'ncirig lugs I 1 one' of which has a "pin noti'showib "whicheng'a'ges a corresponding hole "in reel 'li l5 'to'fform a driving connection between mer er "and the 'purrip. :Centeiingi support 1'13 is located on bracket [8, and'is"provided with'a"'lever f9 which'jcoacts withlthe inclineds'urfacefi0f to 'ldck the reel into vposition, and also. "to provide a rapid "unlocking means. i

Thereel H has Wound'on itaigivenlengthfof wire 24. *After'the reel 'hasbeenfplaeediri po'sition'o'ne en'd' ZE o'f'the'wirei'slpassed overiaro ller 26, mounted on supports 21, and then around la "p1illyv28 of 'a'conventio'nal; jockey arm 29. After leaving thefp'uney zs the wire'isred'alon with the .'oth'er wires "which .ga-r'e to tro'rm {the cable through a positioning plate (not shown) "'ahd into .a-strandingapparatus. I j pump [5 has-alclosed ciicuit "consisting of pipes 33 21111 suitable cbnnectionsffl icon- I tained in the pipe .cir'cuitis a" quantity of oil. or other similar liquid which has suspend in ,it finely divided particles having magnetic -.-pr'op'er ties, wl1 ich combine with the liquid 'to iormiia magnetic fluid suspension. V V Encircling one section of pipe '33 isia .-c"oil 35 formed of conductive wire-which is -woun d on a spool 36. Terminals 3! correspond tot h ev two opposite ends ofthe coil and these terminals are connected through leads 3'8=to-termina1s1-3$of a rheostat 40. A-battery 4l is .connected---in one of the leads 38 to provide a-sourceof potential for :the coil 35. 1

'The rheostat 40 'has'a tubular extension- 42 which is threaded through a-holeinrbracket-fl and held in place by nuts 44. The movable element-45 of therheostat is mounted on shaft 46 which is positioned within thetubular extension 42, and held in place at its upper endby'housing 41. Mouhted onthe shaft/46 is a disc "48 having the jockey'armZS rigidly connected thereto, so that the disc'a'ndsh'aft arecaused to rotateby any movement of the arm along 'the'path orwire eed w a Withrefeflnce to Figure- 3, 'a rod '53 'ismoiinted These When the coil 35 is energized, a magnetic field is set up through that part of the magnetic fluid;

suspension in the pump circuit which is in the,

vicinity of the coil. This causes the-particles; in the suspension to align themselves in. the magnetic field, and thus tend to solidify that partof the suspension affected by the magnetic field. This solidification, which amounts to a local increase in the viscosity of the fluid suspension, increases the load on the pump l5 and causes it to act as a brake on the reel l I which drives it.

By varying the current through the coil 35 the degree of solidification of the suspension and therebythe pressure against which the pump must, operate may be varied. This variation affords a means of control of the speedof the reel II and accordingly control of the tensionin the wire 25. Automatic regulation of the wire tension is attained by using the jockey arm 29, whose movements along the path of the wire is directly controlled by the wire tension, to vary the resistance of the rheostat t0 and thus the current passing through the coil. If the. wire tension gets too low, the jockey arm will move in'a direction opposite to that in which the wire is fed into the stranding apparatus. This movement rotates the disc 48 which turns the shaft 46 on which the movable element of the rheostat is mounted so that the resistance of the coil circuit is reduced. This will increase the coil current, which will increase the degree of solidification ofthe magnetic'fluid suspension and cause the wire tension to increase to a normal desired.

gree of solidification of the suspension will then decrease and lighten the load against which the pump operates. This allows the reel H to increase in speed and so reduces the wire tension.

The spring 56 on the side of the rod 53 corresponding to the direction of wire feed, causes the jockey arm to seek a position where the compression on the spring equals the pull on the jockey arm caused by the feeding of the wire. The two springs 56 also act to limit the total distance which the jockey arm may travel, and aid the rheostat action in providing a smooth regulation of the desired tension.

It is a simple matter of adjustment to coordinate the allowable movement of the jockey arm with the rheostat settings to provide a smooth and automatic regulation of the wire tension.

One practical advantage of the proposed apparatus is that when it is desired to stop the stranding process for any reason, the increased loading on the pump caused by the resultant;

at rest to remain under tension by acting as a brake on the reel and preventing the loss of tension which would occur if the reel were free toturn.

By using the invention herein described it is possible to maintain a uniform wire tension with apparatus tha-tis simple inoperation and which .Frequires a'minimum of.maintenance'due to the almost complete absence of frictionally engaging parts.

It is to be understood that the above-described arrangements are simply illustrative of the application, of the principles of the invention.

,Numerous other arrangements may be readily devised by those skilled in the art which will embody the principles of the invention and fall within the spirit and scope thereof.

Whatis claimed is:

1. In a wire tension regulating device, the combination with a rotatable reel of wire and means for rotating the reel by withdrawing-wire from it, of a closed pathcontainingmagnetic particles suspended "in a liquid, a pump driven by rotation of there el for circ'ulatingthe liquid in the path, and means controlled'by the tension in the wire for varying the'speed ofzthe reel by varying the viscosity of the liquid suspension circulated by the pump.

2. In a wire tension"regulating device, the combination with a rotatable reel'of' wire and means for rotating the reel'by withdrawing wire from it. of a closed path containing magnetic particles suspendedin a liquid, a pump driven by rotation of the reel for circulating the liquid-in the path, means for subjecting the liquid to the action of a magnetic field, and means controlled by the'tension in the wire for varying the speed of the reel by varying the strength of the magnetic field.

3. In a wire tension regulating devicethe combination with a rotatable reel of wire, means for rotating the reel by withdrawing wire from it, and a member varying in position-with the changes in tension in the wire being withdrawn, of a closed path containing magnetic particles suspended in a liquid, a pump driven by rotation of the reel for circulating the liquid in the path, means for subjecting the liquid to the actio'n' of a magneticfi eld and meansc'ontrolled by the member for varying the speed: of the-reel by varying the strength of the magnetic field.

4. In a wire tension regulating device, the combination with a rotatable reel of wire and means for rotating the reel by withdrawing wire from it, of-a closed path containing magnetic particles suspended in a liquid, a pump drivenlb'y rotation of the reel for circulating the liquid in the path, and means for varying the speed of the reel by varying the viscosity of the liquid suspension circulated by the pump, said means'c'omprising a coil of conductive wire in proximity to the closed path, an energizing circuit for the coil, and means for varying the current passing through the coil.

5. In a wire tension regulating device the combination with 'a rotatable reel of wire, means for rotating the reel by withdrawing wire from it, and an arm varying in position; with the changes in tension in the wire being withdrawn. of a closed path containing magnetic particles suspended in a liquid, a pump driven by rotation of the reel for circulating the liquid in the'path, means including a coil of conductive wire and an energizing circuit for saidcoil for subjecting the liquid to the action of a magnetic field, and

a variable resistance connected in the coil energizing circuit for varying the strength of the field, said resistance being controlled by movement of the arm.

GORDON C. SPILLMAN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,144,694 Delaney June 29, 1915 2,006,819 Zschach July 2, 1935 2,123,936 Dreyfus et al July 19, 1938 2,219,196 Nystrom et al Oct. 22, 1940 2,334,165 Abbott Nov. 16, 1943 Germany June 7, 1940 OTHER REFERENCES The Magnetic Fluid Clutch-of Jacob Rabinow, National Bureau of Standards Technical Report 1213. Received Div. 68 U. S. Patent Office March 30, 1948.

The Magnetic Fluid ClutchJacob Rabinow,

15 A I E E Technical Paper 48-238 made available for printing September 3, 1948, 192-84. 

